The present invention relates to a thin antiferromagnetic film with high corrosion resistance and, more particularly, to an antiferromagnetic thin film applied for restraint of Barkhausen noise of a magnetoresistance-effect element in a reproducing magnetic head for a magnetic disk apparatus or the like.
In order to prevent generation of Barkhausen noise of a magnetoresistance-effect element employing permalloy (a generic name of a Ni-Fe highly-permeable alloy containing 35 to 90 weight % of nickel), it has already been proposed to utilize a method such that a thin antiferromagnetic film is brought into contact with at least one portion of a thin permalloy film so as to restrain movement of magnetic domain walls of the permalloy by an exchange bias field generated from the exchange coupling between the permalloy film and the antiferromagnetic film (refer to JP-A-62-40610 and JP-A63-117309). An Fe-Mn alloy is used as a material for the antiferromagnetic film.
However, because one part of the magnetoresistance-effect element including an Fe-Mn alloy film is normally exposed to the atmosphere, weakness in corrosion resistance of the Fe-Mn alloy causes a problem. The above-mentioned prior method lacks practicality because of the poor corrosion resistance of the Fe-Mn alloy.
It has also been proposed for improving the corrosion resistance of the Fe-Mn alloy, to add Ti, Rh, Cr or the like to that alloy (refer to JP-A-63-273372 and JP-A-1-21389); however, the corrosion resistance of the Fe-Mn alloy to which Ti, Rh, Cr or the like is added, is not still satisfactory and it is therefore desired to further improve the Fe-Mn alloy in corrosion resistance.